جستجوی مقالات مرتبط با کلیدواژه « نقطه ی کنترل » در نشریات گروه « عمران »

Considering appropriate lateral load pattern and deter- mining target displacement for bridges in nonlinear static pushover (NSP) analysis have been important issues for researchers. There are two conventional load patterns in the standard codes of practices which are called:1- Mode shape proportional load pattern, 2-Mass propor- tional load pattern.
Capacity Spectrum Method (CSM) is one of the ap-proaches applied in determining target displacement of structures usually using the rst mode proportional load pattern. In conventional (CSM) method for determining the spectrum capacity curve during NSP analysis, the base shear of the multi degrees of freedom system versus displacement of the control point is drawn using the rst mode proportional load pattern, and then is converted to spectral displacement and spectral acceleration format. Converting base shears and control point displacements into spectral accelerations and displacements is based on the assumption that the dynamic behavior is dominated with only one of the natural vibrational mode shapes which is assumed to be constant and not changing dur- ing the (NSP) analysis. Assessing this assumption for horizontally curved bridges shows that the lateral load patterns are e ected with combination of modes and are not proportional to one especial mode shape. In this context, mass proportional load pattern is usually used to consider the e ects of some special pre-speci ed mode shapes in (NSP) analysis. In this research, the (CSM) method is further devel- oped and a method is proposed for determining target displacements using the mass proportional load pattern. In the proposed method, the capacity spectrum is drawn using mass proportional load pattern based on the dis- placement vector in the linear range instead of some speci ed mode shapes. Therefore, the developed pro- posed method is not dependent on some pre-speci ed modes of vibration and the e ects of all modes of vi- bration are considered simultaneously. The eciency of the proposed method is proved by determining target displacements of control points on a horizontally curved bridge using the proposed method and then comparing the results with the results of incremental dynamic anal- ysis (IDA).